Printing plate mold



Dec, 15, H' A W. WOOD PRINTING PLATE MOLD 5 Filed April e, 1929 ll'l'llll Patented Dec; 15, 1931 UNITED v,STATES HENRY A. WISE Woon, or NEWl YORK, N.

l j its nssidNon Tofwoon MA,- CHINERY CORPORATION, or New` YORK,

,"nconroRA'rIoNoF vIRGrNIn PRINriNGrLTE ttoLn"1^' Application led April 6,

This invention relates to a `mold for casting a printingplate adapted to be held down on a printing cylinder at the longitudinal edges of the plate. The principal objectsof the invention are to provide the plate with of breakage of the edge of the plate vdue to its pounding back and forth repeatedly. Other objects and advantages of this invention will appear hereinafter. f y

Reference is to be had to the accompany#V F ig. 1 is a plan of a printing cylinder,

partly insection, showing the cast plate;

Fig. 2 is an enlarged view ofthe same.; Fig. 3 is a sectional'view on the-line 3 3 V'of Fig. 2, and` Fig. Ll is a transverse sectional view of the edge of a casting mold in which such a'printing plate is cast.

Printing plates usuallyY are held on the printing cylinders by end clamps only. These press agalnst the semi-circular ends of theV plates. The edges of the plate which are straight and parallel with the axis .of the printing cylinder are not clamped. The result is that'at high running speeds there `a tendency for the center portions of these straight edges to be thrown out awayffrom theV cylinder by centrifugal force. This bulges out the edgesof the plateand the part which is necessarily farther away from the'I center of the cylinder than theV rest of the plate bears against the paper on theimpression cylinder with vexcessive forceand very dark printing results. The repetition of this action of pressing the edges ofthe plates back against the cylinder as they pass through the impression, then throwing them out by centrifugal force, resultsin fatigue ofthe metal and sometimes a piece'breaks out of the edge of theplate. This is apt tocause j considerable damage. Besides thecentrifu- Vgal action just described, the bowingout of theedges of the plates is apt to be causedor.

increased by the setting in of the clamps on j both ends of the plate. The natural ten- `denc'y ofnaman working'on la speed press is to keep pulling his clamps tighter so; that the plate will not fly olf, thus accentuating thev bowing outwardly of the edges i v i ofthe plate; means to facilitate holding down the straight In order to prevent these difficulties,I provide each plate' 10, in addition to its holding means at its semicircular ends, with a relcess 11 in each straight edge, preferably about half way'betweenthe ends.V I also provide margin bars 12 extending along the straight edges of the plateswithtwo tongues 13on opposite sides, each one extending into a recess 11 inthe plate adjacent thereto, I have shown these tongues as of considerable length `,so as to hold the .plates downandas having considerableclearance inthe recesses at the as usual, as is theV matrix bar 18 and the 75:

matrix19. On the matrixv clip 20, however, there is an additional feature in the form of .a projecting tongue 21 which is properly sized andV located in the mold and extends longitudinally along the edge thereof. It will be obvious `that this tongue projects :into the plate 10` being'cast'soas to form a longitudinal recess 11 along the edge thereof and that there is nothing aboutiits shape tolprevent the taklng of the matrix 'clip out of the mold after the casting is completed.

` It will be seenlthat by providing the castj ing molds with this simple Vadditional feature and introducing the margin bars12 with their tongues ori the plate cylinders, the difficulties which have been described above are entirely eliminated.

No claim is made herein to thevfeatures of the printing plate itself or the way of holding it on the printing cylinder because these features Aconstitute the subject-matterof my divisional application Serial No. 507,833, led January10,1931. .f Y

Although I have illustrated and described only one form of the invention I am aware of rooV Y the fact that modifications can be made therein by any person skilled in the art Without departing from the scope of the invention as expressed in the claim. Therefore, I do not Wish to be limited to the exact form of construction heren shown and described, but what I claim is:-

In a mold for casting a stereotype printing plate, the combination with the core and back, of a matrix clip having a tongue projecting tangentially into the mold Vcavity and extending longitudinally thereof between the back Y Y and the core. A

In testimony whereof I have hereunto affixed my signature.

` HENRY A. WISE WOOD. 

